POLISH POLAR RESEARCH (POL. POLAR RES.)
8
4
403—410
1987
Ryszard OCHYRA
Department of Bryology
and Lichenology
Institute of Botany
Polish Academy of Sciences
Lubicz 46
31-512 Kraków, POLAND
What is Dichelyma antarcticum
C. Muell.?
ABSTRACT: On the basis of comparable habit, leaf morphology and leaf cell
pattern, leaf and stem sectional anatomy, D i c h e l y m a a n t a r c t i c u m C. Muell. is reduced
to synonymy with B l i n d i a m a g e l l a n i c a C. Muell.
Key w o r d s : Subantarctica, bryology, taxonomy, D i c h e l y m a , B l i n d i a
1. Introduction
Dichelyma Myr. is a small genus of pleurocarpous mosses consisting
of five species occurring exclusively in the Northern Hemisphere (Welch
1960), although fifteen specific names have been correctly combined with
this generic name (Wijk et al. 1962, 1969). Of these, only one name refers
to the species described from outside the Holarctic, namely to Dichelyma
antarcticum C. Muell. from the austral region. According to Welch (1960)
the type collection of this species was examined by Frances E. Wynne,
who regarded it as Drepanocladus aduncus (Hedw.) Warnst. var. capillifolius
(Warnst.) Grout. Since the latter taxon has never been recorded in the
Southern Hemisphere, I critically re-examined type material of D. antarcticum
as part of a revision of the extra-Holarctic Amblystegiaceae.
Muller (1883, 1889) described Dichelyma antarcticum, the type of which
was collected on Kerguelen Islands by F. C. Naumann during the course
of the "Gazelle" Expedition around the world in 1874—1876. He compared
this newly described species to some slender and delicate forms of Dichelyma
capillaceum (With.) Myr. from eastern North America and northern Europe
from which it differed in having much narrower and always straight
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Ryszard Ochyra
leaves with well-developed alar cells. It should be noted that MOller (1889)
mentioned also D. australe Hampe, another species of this genus in the
Southern Hemisphere. This herbarium name has never been validly published
and it is missing from all bryological compendia including Index Bryologicus
(Paris 1904) and Index Muscorum (Wijk et al. 1962, 1969). Unfortunately,
the identity of this taxon must remain unknown, since no original material
of D. australe is available from Hampe's herbarium at BM.
2. Material
Dichelyma antarcticum was described from two collections (МйНег №89),
originals of which were almost certainly destroyed at the Berlin fire in 1943.
However, duplicates of both syntypes have been located from herbaria in
Stockholm (S) and London (BM). In both instances the material, though
sterile, is sufficient to examine characters that are indispensable for establishing
the identity of this species.
3. Results and discussion
The type material of D. antarcticum (Figs. 3—11) contains plants of medium size forming loose, lustrous, intricate tufts that are fulvous or brown-green in the uppermost portions, becoming brownish black to black and
frequently denuded of leaves below. The stems are 1—9 cm high, slender,
flexuose, simple or occasionally branched. In transverse section they are
subround, without central strand and consist of 2—3, occasionally even 4,
rows of strongly incrassate, small, brown cortical cells that surround 3—4
rows of larger, relatively thin-walled medullary cells. The leaves are crowded,
straight to flexuose, occasionally slightly secund, erect to erect-patent when
dry and wet, subulate from lanceolate, concave base and variable in size
(2.5—4.5 mm long, 0.3—0.4 mm wide at base). The subulae are very fine,
about 2 times as long as laminae, obtuse or acute and amost smooth to
obscurely denticulate at the apex. The leaf margins are entire and erect
to incurved. The costa is single, strong, 65—80 ц т wide at the base and
fills the entire subula. In transverse section it is subelliptical, somewhat
flattened ventrally and is composed of incrassate, nearly homogeneous
cells. The leaf cells are long, straight, not porous, linear-elongate to narrowly
elliptic-rectangular throughout the lamina and with ends truncate or oblique.
The cell walls are thick and smooth or slightly roughened what is obvious
only in transverse section. They are variable in size, 3—7 ц т wide, 20—40 ц т
long in the upper part of the lamina and becoming longer towards the
What is Dichelyma antarcticum?
405
Figs I—11. B l i n d i a m a g e l l a n i c a Schimp. ex C. Muell. 1—5: leaves; 6: transverse sections
of leaf; 7: transverse section of stem; 8: apical cells of leaves; 9: lamina cells below the
excurrency of the costa; 10: mid-leaf cells; 11: angular cells.(1—2 from isotype of B l i n d i a
g r a c i l l i m a Mitt. — LE; 3—11 from isolectotype of D i c h e l y m a a n t a r c t i c u m C. Muell. — S).
base, reaching up to 65 ц т in length. The alar cells are brown to orange-brown,
subquadrate to short rectangular at margins, 20—40 |лт long, 15—20 ц т
406
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wide, with strongly incrassate and smooth walls. They form very distinct,
inflated and decurrent auricles that are separated from the costa by 5—8
rows of orange-brown cells at the insertion. Neither sporophytes nor sexual
organs have been found on the type material.
It should not be too strange that, in the absence of sporophytes,
plants growing submerged in lakes on Kerguelen Islands made Muller think
of Dichelyma capillaceum, which grows in identical habitats. When casually
seen, some slender habitat expressions of this species resemble indeed the
plants described as D. antarcticum. However, Dichelyma is a well defined
genus diagnosed by a set of peculiar characters that permit its immediate
recognition from the remaining genera of mosses. It is a pleurocarpous
moss with distinctly or obscurely trifarious leaves that are keeled and
more-or-less conduplicate. In addition, cells are linear-flexuose to linear-rhomboidal throughout the lamina with distinctly attenuate ends, and the
alar cells itre not particularly different from the adjoining lamina cells.
These characters are totally lacking in D. antarcticum, which is a moss having
channelled leaves that are arranged in many ranks on the stem. Additionally,
the lamina cells in D. antarcticum are linear and straight with truncate
or oblique ends, and alar cells form very distinct and decurrent auricles.
Since Dichelyma antarcticum appears to be an acrocarpous, dicranoid
moss having simple or only occasionally branched stems, it obviously has
no alliance with the genus Drepanocladus (C. Muell.) G. Roth as suggested
by F. E. Wynne (Welch 1960). Drepanocladus is a pleurocarpous moss
having strongly branched stems and the superficial similarity of the leaves,
including the strong and long excurrent costa and distinct angular cells,
of D. aduncus var. capillifolius and the plants that are currently named
Dichelyma antarcticum is doubtless due to convergent evolution of very
remotely related plants that thrive in similar habitat conditions.
When completing a monograph of the Fontinalaceae, W. H. Welch examined the type collections of D. antarcticum at BM and S. She definitely
precluded any alliance of this species with Dichelyma and suggested its
relationship with the genus Blindia В., S. & G. as visible on labels with
annotations attached to the type material. However, this suggestion has not
been foUowed by the formal transfer of this species to Blindia as well
as there is no mention of that in the published monograph of the Fontinalaceae (Welch 1960).
Having examined the type collections of Dichelyma antarcticum as well
as type collections of several species of Blindia from the Southern Hemisphere,
especially those described from Kerguelen Islands^ I came to the conclusion
that W. H. Welch was correct in suggesting the realignment of D. antarcticum
in its true relationship. This species is indeed a Blindia and many structural
characters confirm this conclusion. Blindia is a small acrocarpous moss
genus consisting of 16 species that are predominantly distributed in the
What is Dichelyma antarcticum?
407
Southern Hemisphere (Bartlett and Vitt 1986). Historically, species of Blindia
in the austral region have been misunderstood. From one hand, a lack
of appreciation of the morphological variation shown by some species has
led to a number of new species being described. Many of these have been
reduced to synonymy, mainly with B. magellanica Schimp. ex C. Muell.,
by Bartlett and Vitt (1986) in the latest survey of species in this genus.
On the other hand, however, prior to this survey an ill-defined concept
of Blindia resulted in the inclusion in it many species that are evidently
anomalous in this genus. These were mostly species of various dicranoid
genera, such as Ditrichum Hampe, Dicranoweisia Lindb. ex Milde, Verrucidens
Card., Chorisódontium (Mitt.) Broth, and Holodontium (Mitt.) Broth., which
are externally very similar to Blindia, but different peristome structure
precludes their closer relationships. The safest distinguishing character between
sterile plants of Blindia and the above mentioned genera is the anatomical
structure of the costa. In Blindia the costa is composed of practically
homogeneous cells in transverse section, whereas in dicranoid genera it
consists in transverse section of well-developed adaxial and/or abaxial stereid
bands and large central guide cells (Zanten 1971, Bartlett and Vitt 1986).
Of several species of Blindia that were described from Kerguelen Islands,
the type collection of B. gracillima Mitt, was especially pertinent to comparison
with Dichelyma antarcticum. This species was described by Mitten (1879)
from material collected by A. E. Eaton during the Transit of Venus Expedition
in the years 1874—1875. The type material of B. gracillima that I examined
in Leningrad (LE) is in fine fruiting condition, and the typically seligeioid
peristome confirms its correct generic placement. Comparison of types of
both Blindia gracillima and Dichelyma antarcticum revealed excellent correspondence in all critical and taxonomically important characteristics. This refers
to the habit, size and coloration of the plants, leaf shape and areolation
as well as to the anatomical structure of the costa and the stem. The
persuasive similarity of the plants of B. gracillima and D. antarcticum led
me to the conclusion that both species are inseparable from one another
and should be considered synonymous.
Blindia gracillima has recently been examined by Bartlett and Vitt
(1986) who found that it falls within the range of variability of Blindia
magellanica and synonymized both species, of which the latter has priority
(Muller 1862). This species has a pan-temperate geographical range in the
Southern Hemisphere, occurring in temperate regions of southern South
America, Australasia and on all sub-Antarctic islands from South Georgia to
Kerguelen Islands. In addition, this typically antipodal species is disjunctively
distributed in the paramos of the northern Andes in Colombia and Ecuador,
in the mountains in southeastern Brazil, in Lesotho in South Africa and
in New Guinea (Bartlett and Vitt 1986).
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Ryszard Ochyra
Blindia magellanica is a variable species, a feature typical of. all species
growing in rheophytic or otherwise hydrophytic habitats. The setaceous
leaves of Blindia gracillima (Figs 1—2) and Dichelyma antarcticum (Figs 3—5)
have the very fine subulae that are about twice as long as the laminae
and in this character they approach some reduced, aquatic forms of
Blindia robusta Hampe, another antipodal species of Blindia having a temperate
amphipaciflc distribution pattern. However, the large and inflated angular
cells forming decurrencies, as well as the shorter and narrower lamina cells
immediately separate the plants from Kerguelen Islands from B. robusta.
Both B. gracillima and D. antarcticum appear to represent extreme aquatic
expressions of Blindia magellanica that differ from small terrestrial forms
in longer subulae, but there is a steady continuum in the length of subulae
in various plants growing in fluctuating habitat conditions. Consequently,
Dichelyma antarcticum is considered synonymous with Blindia magellanica.
Blindia magellanica Schimp. ex C. Muell., Bot. Zeit. 20: 328. 1862.
Syn. nov.: D i c h e l y m a a n t a r c t i c u m C. Muell., Bot. Jahrb. 5: 82. 1883. Type: all new
taxa proposed by Muller (1883) are listed in the section entitled "I. Bryologia Kerguelensis";
later, Muller (1889) wrote: Ins. Kerguelen, loco non indicate 12. Januario 1875. in aquosis.
In lacu Margot ad lapides Novbr. 1874 [Lectotype (chosen here): "Ex Museo botanico
Berolinensi. D i c h e l y m a a n t a r c t i c u m C. Mull. n. sp. Kerguelensl. Dr. J^ąumąnn. 1874" — BM!;
isolectotype: S-Roth (2 specimens)! Syntype: "Ex Museo botanico Berolinensi. D i c h e l y m a
a n t a r c t i c u m var. nanum
C. Mflll. Kerguelen Margot 800', Nov. 1874, Dr. Naumann" —
S-Mdiler!].
I am greatly indebted to the curators of herbaria at BM, LE and S for making available
the specimens on which this study was based. My wife, Halina, completed the illustrations
and I am very thankful for her aid. I wish to express my appreciation for the comment
on the manuscript of Dale H. Vitt, Edmonton, Canada.
4, References
Bartlett J. K. and Vitt D. H. 1986. A survey of species in the genus B l i n d i a (Bryopsida,
Seligeriaceae). — New Zealand J. Bot. 24: 203—246.
Mitten W. 1879. Musci. In: An account of the penological, botanical, and zoological
collections made in Kerguelen's Land and Rodriguez during the Transit of Venus Expeditions, carried out by order of Her Majesty Government in the years 1874—75. — Phil.
Trans. R. Soc. London 168 : 24—39.
Muller С. 1862. Addimenta ad Synopsin Muscorum nova.— Bot. Zeit. 20: 327—329;
337—339; 348—350; 361—362 ; 373—374; 381—382 ; 392—393.
Mflller C. 1883. Die auf der Expedition S. M. S. "Gazelle" von Dr. Naumann gesammelten
Laubmoose. — Bot. Jahrb. 5 : 76—88.
Muller С. 1889. Laubmoose (Musci frondosi). — In.: Die Forschungsereise S. M. S. "Gazelle"
in den Jahren 1874 bis 1876 unter Kommando des Kapitan zur See Freiherrn von
ScMeinitz. 4. Botanik. — Hygrographischen Amt des Reichs-Marine-Amts, Berlin, 1—64.
Paris E . G . 1904. Index bryologicus sive Enumeratio muscorum ad diem ultimam anni 1900
cognitorum adjunctis synonymia distributioneque geographica locupletissimis. Ed. 2, 2. —
Librairie Scientifique A. Hermann, Paris, 375 pp.
What is Dichelyma antarcticum?
409
Welch W. H. 1960. A monograph of the Fontinalaceae. — Martinus Nijhoff, The Hague, 357 pp.
Wijk R. van der. Margadant W. D. and Florschiitz P. A. 1969. Index Murscorum. Vol. 2
(D-Hypno).
Regn. Veget. 26: 1 -535. Utrecht.
Wijk R. van der, Margadant W. D. and Florschiitz P. A. 1969. Index Murscorum. Vol. 5
(T-Z, Appendix). — Regn. Veget. 65: I—XII +1—922. Utrecht.
Zanten B.O. van. 1971. Musci.—In: E. M. van Zindereh Bakker sr.. J. M. Winterbottom
and R. A. Dyer (eds). Marion and Prince Edward Islands. Report on the South
African Biological and Geological Expedition 1965- 1966.—A. A. Balkema, Cape
Town, 173—227.
Received July 5. 1987
Revised and accepted July 20. 1987
5. Streszczenie
W trakcie niemieckiej wyprawy naukowej dookoła świata w latach 1874—1876 na statku
..Gazelle" dr F. С. Naumann zebrał w 1874 roku na Wyspie Kerguelen nowy gatunek
mchu opisanego przez Mullera (1883. 1889) jako D i c h e l y m a a n t a r c t i c u m С. Muell. Był to
pierwszy i jak dotąd jedyny gatunek tego rodzaju znany z południowej półkuli. W 1960 -roku
W. H. Welch w mortbgrafii rodziny Fontinalaceae stwierdziła, że gatunek D . a n t a r c t i c u m był
zbadany przez Frances E. Wynne, która zsynonimizowała go z D r e p a n o c l a d u s aduncus
(Hedw.) Warnst. var. c a p i l l i f o l i u s (Warnst.) Grout.
Ponowne zbadanie obu syntypów D i c h e l y m a a n t a r c t i c u m , zdeponowanych w zielnikach
w Londynie (BM) i Sztokholmie (S) doprowadziło autora niniejszego artykułu do stwierdzenia,
że gatunek ten nie ma bliższego związku ani z rodzajem D r e p a n o c l a d u s (C. Muell.)
G. Roth. ani z rodzajem D i c h e l y m a Myr. Pierwszy z nich jest typowym mchem bocznozarodniowym. o łodydze bardzo silnie porozgałęzianej. Również D i c h e l y n m jest mchem silnie
rozgałęzionym, który cechuje się trójrzędowym ułożeniem liści na łodydze oraz brakiem
komórek skrzydłowych liści. Tych cech zupełnie jest brak u D i c h e l y m a a n t a r c t i c u m . Natomiast
kształt liści i ich budowa anatomiczna u tego gatunku wykazują bardzo wielkie podobieństwo
do B l i n d i a m a g e l l a n i c a Schimp. ex C. Muell. Liście u obu tych gatunków posiadają bardzo
długi, szydlasty kończyk. który jest eałobrzegi lub niewyraźnie ząbkowany na samym szczycie.
Poza tym typ D i c h e l y m a a n t a r c t i c u m charakteryzuje się dalszymi unikalnymi cechami, których
brak jest w rodzaju D i c h e l y m a : (1) żyłka liścia wypełnia cały kończyk; (2) komórki
skrzydłowe liścia są silnie zróżnicowane, brązowe lub pomarańczowo-brązowe i tworzą zbiegające uszka; (3) komórki blaszki liściowej są grubościenne. wąsko-prostokątne, 20—40 ц т
długie i 3—7 ц т szerokie; (4) komórki żebra w przekroju poprzecznym są homogeniczne.
Wszystkie te cechy są typowe dla B l i n d i a m a g e l l a n i c a Schimp. ex C. Muell., polimorficznego
gatunku o wokólbiegunowym typie zasięgu na południowej półkuli. D i c h e l y m a a n t a r c t i c u m
jest szczególnie podobna do B l i n d i a g r a c i l l i m a Mitt.. gatunku opisanego przez Mittena (1879)
także z Wyspy Kerguelen. Jednakże Bartlett i Vitt (1986) uważają ten gatunek za wodną
modyfikację В m a g e l l a n i c a nie mającą żadnej wartości systematycznej. Również D i c h e l y m a
a n t a r c t i c u m posiada ten sam zespół cech diagnostycznych i musi być traktowana jako nowy
synonim B l i n d i a m a g e l l a n i c a .